Traian Basescu

The prospect of President-elect Donald Trump striking a grand bargain with Russian President Vladimir Putin is unnerving to many traditional U.S. allies, but few stand to lose more than the pro-American leaders of countries in Central and Eastern Europe. Those leaders, fighting on the front line of the battle against Putin's drive to upend the democratic world order, are asking Trump to think twice before choosing the wrong side.

"Putin does not seek American greatness. As your allies, we do," 17 current and former officials from a range of Central and Eastern European countries wrote in a letter to Trump that I obtained. "As your treaty-bound allies, we appeal to...